JP5800459B2 - Polyoxymethylene resin composition and molded article - Google Patents

Description

  The present invention relates to a polyoxymethylene resin composition and a molded body.

  Polyoxymethylene resins are widely used in various mechanical parts, OA equipment, and the like as engineering resins that have balanced mechanical properties and excellent friction and wear performance. However, conventionally, the polyoxymethylene resin does not have a sufficient level of impact resistance. For this reason, attempts have been made to prepare a polyoxymethylene resin as a composition with an elastomer component. Examples of such attempts include a technique for blending a polyurethane resin with a polyoxymethylene resin (for example, see Patent Documents 1 and 2), and a technique for blending an olefin elastomer and polyurethane with a polyoxymethylene resin (for example, Patent Document 3). (See, for example, Patent Document 4), and polyoxymethylene in which a thermoplastic polyurethane and a polyether block copolyamide are blended (for example, Patent Documents). 5) is known. Among these techniques, a technique for adding polyurethane to a polyacetal resin has been put into practical use. However, these compositions do not have excellent vibration damping performance and are also extremely inferior in sliding performance, so that they are not suitable for uses intended for vibration damping and noise reduction.

  As a material that can be developed for applications intended for damping and silencing, a composition comprising a thermoplastic polyurethane block, a resin comprising a block of a conjugated diene compound unit and an aromatic vinyl compound unit and a polyacetal resin ( For example, see Patent Document 6). However, although this composition has excellent vibration damping performance, it is inferior in sliding performance, and therefore its noise reduction effect is small.

  Therefore, as a technique for solving the above problem, the present inventors have found that a main dispersion peak of tan δ in a viscoelastic spectrum having at least one polyoxymethylene resin and a hydrogenated aromatic vinyl-conjugated diene random copolymer is obtained. The composition (refer patent document 7) which mix | blended the polymer of 60 degrees C or less and the polyolefin resin arbitrarily in the ratio of the specific range was proposed.

JP 59-155453 A JP 59-145243 JP 54-155248 A JP-A-62-036451 JP 63-280758 A JP-A-9-310017 International Publication No. 2005/035652

  Although the composition proposed in Patent Document 7 is a composition that has solved the above-mentioned conventional problems, such as excellent vibration damping performance and silencing effect, the oil resistance is not sufficient, and there is room for further improvement. is there.

  The present invention has been made under the above circumstances, and is a composition containing a polyoxymethylene resin, which has excellent oil resistance in addition to excellent impact resistance and vibration damping performance. It aims at providing the provided polyoxymethylene resin composition and its molded object.

In order to impart excellent oil resistance to the polyoxymethylene resin composition in addition to excellent impact resistance and vibration damping performance, the present inventors have studied various polymer compounds and completed the present invention. . That is, the present invention is as follows.
[1] Heavy weight having at least one (A) polyoxymethylene resin and (B) vinyl aromatic compound-conjugated diene compound copolymer block, and having a main dispersion peak of tan δ in the viscoelastic spectrum of 60 ° C. or lower. A combined or hydrogenated product thereof, and (C) an oil,
The content of the component (A) is 20 to 99.5 parts by mass with respect to 100 parts by mass of the total of the component (A), the component (B), and the component (C), and the component (B) ) Component content is 0.25-79.2 parts by mass,
The content of the component (C) is 1 to 50 parts by mass with respect to a total amount of 100 parts by mass of the component (B) and the component (C),
The component (A) includes (A-1) a polyoxymethylene block copolymer having a number average molecular weight of 10,000 to 500,000 represented by the following general formula (1):
The component (C) is a polyoxymethylene resin composition comprising a mineral oil softener or a synthetic resin softener selected from the group consisting of dimethylsilicone, methylphenylsilicone and methylhydrogensilicone .
^{H-R 3 -O- (CR 1} 2) k-R 4 - (CR 1 2) k-O-R 3 -H (1)
(Wherein R ¹ represents a chemical species selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group, and a substituted or unsubstituted aryl group, and may be the same or different from each other; Represents an integer of 2 to 6. R ³ represents a block having a plurality of oxymethylene units represented by the following general formula (2a) and oxyhydrocarbon units represented by the following general formula (2b); The methylene unit and the oxyhydrocarbon unit are present randomly, and the content of the oxymethylene unit is 95 to 99.9 mol with respect to 100 mol% of the total amount of the oxymethylene unit and the oxyhydrocarbon unit. %, and 0.1 to 5 mol% content of the oxyhydrocarbon units, number average molecular weight of the average of the two R ³ is 5000 to 250000 .R ² is a hydrogen atom, a substituted or unsubstituted Alkyl group, and shows the species selected from the group consisting of substituted or unsubstituted aryl group, which may be the being the same or different, j is an integer of 2 to 6 .R ⁴ represented by the following general formula 2 shows a block having a plurality of ethylene units represented by (3a) and n-butylene units represented by the following general formula (3b), wherein the ethylene units and the n-butylene units are present at random or in blocks. The ethylene unit content is 2 to 98 mol% and the n-butylene unit content is 2 to 98 mol% with respect to 100 mol% of the total amount of the ethylene unit and the n-butylene unit. R ⁴ has a number average molecular weight of 500 to 10,000 and may have an unsaturated bond having an iodine value of 20 g-I 2/100 g or less.)
_{- (CH 2 O) - (} 2a)
− ((CR ² ₂ ) j−O) − (2b)
_{- (CH 2 CH 2) -} (3a)
_{- (CH 2 CH 2 CH 2} CH 2) - (3b)
[2] The component (A) has (A-2) an oxymethylene unit and an oxyalkylene unit having 2 or more carbon atoms, and the oxymethylene unit and the oxyalkylene unit are used in the total amount of the oxymethylene unit and the oxyalkylene unit. It further includes a polyoxymethylene copolymer having an alkylene unit content of 0.1 to 10 mol%, and the mass ratio (A-1) / (A-1) component to the component (A-2) The polyoxymethylene resin composition according to [1], wherein A-2) is 99/1 to 10/90.
[3] The polyoxymethylene resin composition according to [1], wherein the component (A) includes the component (A-1).
[4] The polyoxymethylene resin composition according to any one of [1] to [3], wherein a main dispersion peak of the tan δ in the viscoelastic spectrum of the component (B) is 60 ° C. to −20 ° C. object.
[5] A molded article comprising the polyoxymethylene resin composition according to any one of [1] to [4].

  According to the present invention, a polyoxymethylene resin-containing composition comprising a polyoxymethylene resin composition having excellent oil resistance in addition to excellent impact resistance and vibration damping performance, and a molded product thereof. Can be provided.

  Hereinafter, a form for carrying out the present invention (hereinafter simply referred to as “the present embodiment”) will be described in detail with reference to the drawings as necessary. However, the present invention is not limited to the following embodiment. The present invention can be variously modified without departing from the gist thereof.

  The polyoxymethylene resin composition of the present embodiment (hereinafter also simply referred to as “resin composition”) is (A) a polyoxymethylene resin (also referred to as “(A) component”, the same shall apply hereinafter), B) a polymer having at least one vinyl aromatic compound-conjugated diene compound copolymer block and having a main dispersion peak of tan δ in a viscoelastic spectrum of 60 ° C. or lower, or a hydrogenated product thereof, and (C) an oil; Is a resin composition containing

  Examples of the (A) polyoxymethylene resin used in the present embodiment include polyoxymethylene homopolymers and polyoxymethylene copolymers. A polyoxymethylene homopolymer is obtained by homopolymerizing a formaldehyde monomer or a cyclic oligomer of formaldehyde such as a trimer (trioxane) or tetramer (tetraoxane). Therefore, the polyoxymethylene homopolymer substantially consists of oxymethylene units. A polyoxymethylene copolymer is a formaldehyde monomer or a cyclic oligomer of formaldehyde such as a trimer (trioxane) or tetramer (tetraoxane), ethylene oxide, propylene oxide, epichlorohydrin, 1,3-dioxolane, It is obtained by copolymerizing glycol such as 1,4-butanediol formal, cyclic ether such as cyclic formal of diglycol, and cyclic formal. Further, as polyoxymethylene copolymers, branched polyoxymethylene copolymers obtained by copolymerizing formaldehyde monomers and / or cyclic oligomers of formaldehyde and monofunctional glycidyl ethers, and polyfunctional A polyoxymethylene copolymer having a crosslinked structure obtained by copolymerization with glycidyl ether can also be used.

  Furthermore, (A) a polyoxymethylene resin is obtained by polymerizing a formaldehyde monomer or a cyclic oligomer of formaldehyde in the presence of a compound having a functional group such as a hydroxyl group at both ends or one end, such as polyalkylene glycol. It may be a polyoxymethylene homopolymer having a block component. Similarly, (A) polyoxymethylene resin is a formaldehyde monomer or its trimer (trioxane) in the presence of a compound having a functional group such as a hydroxyl group at both ends or one end, for example, hydrogenated polybutadiene glycol. It may be a polyoxymethylene copolymer having a block component obtained by copolymerizing a cyclic oligomer of formaldehyde such as tetramer (tetraoxane) and cyclic ether or cyclic formal. As described above, both the polyoxymethylene homopolymer and the polyoxymethylene copolymer can be used as the (A) polyoxymethylene resin according to this embodiment. (A) The polyoxymethylene resin preferably contains a polyoxymethylene copolymer.

  When a polyoxymethylene copolymer is obtained using trioxane, the comonomer such as 1,3-dioxolane is generally 0.1 to 60 mol%, preferably 0.1 to 20 mol, relative to 100 mol% of trioxane. %, More preferably 0.13 to 10 mol%. In this embodiment, the suitable melting point of the polyoxymethylene copolymer is 162 ° C to 173 ° C, more preferably 167 ° C to 173 ° C, and further preferably 167 ° C to 171 ° C. A polyoxymethylene copolymer having a melting point of 167 ° C. to 171 ° C. can be obtained by using about 1.3 to 3.5 mol% of a comonomer with respect to 100 mol% of trioxane.

  As the polymerization catalyst used for the polymerization of the polyoxymethylene copolymer, cationically active catalysts such as Lewis acids, proton acids and esters or anhydrides thereof are preferred. Examples of Lewis acids include boric acid, tin, titanium, phosphorus, arsenic and antimony halides. More specifically, boron trifluoride, tin tetrachloride, titanium tetrachloride, phosphorus pentafluoride, Examples thereof include phosphorus pentachloride, antimony pentafluoride, and complex compounds or salts thereof. Specific examples of the protonic acid, its ester or anhydride include perchloric acid, trifluoromethanesulfonic acid, perchloric acid-tertiary butyl ester, acetyl perchlorate, and trimethyloxonium hexafluorophosphate. Among these, boron trifluoride; boron trifluoride hydrate; and a coordination complex compound of an organic compound containing an oxygen atom or a sulfur atom and boron trifluoride are preferable. Specifically, trifluoride is used. Boron diethyl ether and boron trifluoride di-n-butyl ether can be mentioned as suitable examples.

The polyoxymethylene copolymer is produced by a conventionally known method, for example, US Pat. Nos. 3,027,352, 3,803,094, German Patents 1,161,421, 1,495,228, 1,720,358. The polymerization can be carried out by the methods described in the description, No. 3018898, JP-A-58-98322 and JP-A-7-70267. Since the polyoxymethylene copolymer obtained by the above polymerization has a thermally unstable terminal portion [-(OCH ₂ ) _n —OH group], it is difficult to put it into practical use as it is. . Therefore, it is preferable to perform the decomposition and removal treatment of the unstable terminal portion, and specifically, it is preferable to perform the decomposition and removal processing of the specific unstable terminal portion described below. That is, in the decomposition removal treatment of the specific unstable terminal portion, the melting point of the polyoxymethylene copolymer is not lower than 260 ° C. in the presence of at least one quaternary ammonium compound represented by the following general formula (4). The polyoxymethylene copolymer is subjected to heat treatment in a molten state at the temperature of

[R ⁵ R ⁶ R ⁷ R ⁸ N ⁺ ] _n X ⁻ⁿ (4)
Here, in formula (4), R ⁵ , R ⁶ , R ⁷ and R ⁸ are each independently a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms; an aryl group having 6 to 20 carbon atoms; An aralkyl group in which at least one hydrogen atom in a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms is substituted with an aryl group having 6 to 20 carbon atoms; or at least one in an aryl group having 6 to 20 carbon atoms Represents an alkylaryl group in which a hydrogen atom is substituted with a substituted or unsubstituted alkyl group having 1 to 30 carbon atoms, and the substituted or unsubstituted alkyl group is linear, branched, or cyclic. The substituent in the substituted alkyl group is a halogen atom, a hydroxyl group, an aldehyde group, a carboxyl group, an amino group, or an amide group. In the unsubstituted alkyl group, aryl group, aralkyl group, and alkylaryl group, a hydrogen atom may be substituted with a halogen atom. n shows the integer of 1-3. X represents a hydroxyl group or an acid residue of a carboxylic acid having 1 to 20 carbon atoms, a hydrogen acid other than a hydrogen halide, an oxo acid, an inorganic thioacid, or an organic thioacid having 1 to 20 carbon atoms.

The quaternary ammonium compound is not particularly limited as long as it is represented by the general formula (4), but R ⁵ , R ⁶ , R ⁷ , and R ⁸ in the general formula (4) are each independently , Preferably an alkyl group having 1 to 5 carbon atoms or a hydroxyalkyl group having 2 to 4 carbon atoms, and at least one of R ⁵ , R ⁶ , R ⁷ and R ⁸ is a hydroxyethyl group Is particularly preferred. Specifically, tetramethylammonium, tetoethylammonium, tetrapropylammonium, tetra-n-butylammonium, cetyltrimethylammonium, tetradecyltrimethylammonium, 1,6-hexamethylenebis (trimethylammonium), decamethylene-bis- ( Trimethylammonium), trimethyl-3-chloro-2-hydroxypropylammonium, trimethyl (2-hydroxyethyl) ammonium, triethyl (2-hydroxyethyl) ammonium, tripropyl (2-hydroxyethyl) ammonium, tri-n-butyl ( 2-hydroxyethyl) ammonium, trimethylbenzylammonium, triethylbenzylammonium, tripropylbenzylammonium, tri-n-butylbenzene Zirammonium, trimethylphenylammonium, triethylphenylammonium, trimethyl-2-oxyethylammonium, monomethyltrihydroxyethylammonium, monoethyltrihydroxyethylammonium, okdadecyltri (2-hydroxyethyl) ammonium, tetrakis (hydroxyethyl) ammonium, etc. Hydroxides of hydrochloric acid, odorous acid, hydrofluoric acid, etc .; sulfuric acid, nitric acid, phosphoric acid, carbonic acid, boric acid, chloric acid, iodic acid, silicic acid, perchloric acid, chlorous acid, hypochlorous acid Oxo acid salts such as chlorosulfuric acid, amidosulfuric acid, disulfuric acid, tripolyphosphoric acid; thioic acid salts such as thiosulfuric acid; formic acid, acetic acid, propionic acid, butanoic acid, isobutyric acid, pentanoic acid, caproic acid, caprylic acid, capric acid Carboxylic acid salts such as benzoic acid and oxalic acid That. Among these, hydroxide (OH ⁻ ), sulfuric acid (HSO ₄ ⁻ , SO ₄ ²⁻ ), carbonic acid (HCO ₃ ⁻ , CO ₃ ²⁻ ), boric acid (B (OH) ₄ ⁻ ), and carboxylic acid The salt of is preferred. Of the carboxylic acids, formic acid, acetic acid, and propionic acid are particularly preferred. A quaternary ammonium compound is used individually by 1 type or in combination of 2 or more types. Further, in addition to the quaternary ammonium compound, amines such as ammonia and triethylamine, which are known decomposition accelerators for unstable terminals, may be used in combination.

The amount of the quaternary ammonium compound used is preferably in terms of the amount of nitrogen derived from the quaternary ammonium compound represented by the following formula (5) with respect to the total mass of the polyoxymethylene copolymer and the quaternary ammonium compound. Is 0.05 to 50 ppm by mass, more preferably 1 to 30 ppm by mass.
P × 14 / Q (5)
Here, in Formula (5), P shows the density | concentration (mass ppm) with respect to the polyoxymethylene copolymer of a quaternary ammonium compound, 14 is the atomic weight of nitrogen, Q is the molecular weight of a quaternary ammonium compound. Show.

  If the amount of the quaternary ammonium compound used is less than 0.05 ppm by mass, the rate of decomposition and removal of the unstable end tends to decrease, and if it exceeds 50 ppm by mass, the polyoxy after the decomposition and removal of the unstable end is removed. The color tone of the methylene copolymer tends to deteriorate.

  The unstable terminal portion of the polyoxymethylene resin (A) according to this embodiment is decomposed and removed when heat-treated in a state where the polyoxymethylene resin is melted at a temperature of the melting point or higher and 260 ° C. or lower. The apparatus used for the decomposition and removal treatment is not particularly limited, but an extruder, a kneader and the like are preferable. Formaldehyde generated by decomposition is usually removed under reduced pressure. There are no particular restrictions on the method of allowing the quaternary ammonium compound to be present in the polyoxymethylene copolymer, for example, a method of adding it as an aqueous solution in the step of deactivating the polymerization catalyst, a polyoxymethylene copolymer produced by polymerization The method of spraying on powder is mentioned. Whichever method is used, the quaternary ammonium compound may be present in the resin in the step of heat-treating the polyoxymethylene copolymer. For example, a quaternary ammonium compound may be injected into an extruder in which a polyoxymethylene copolymer is melt-kneaded and extruded. Alternatively, when a filler or pigment is added to the polyoxymethylene copolymer using the extruder or the like, a quaternary ammonium compound is first attached to the resin pellet of the polyoxymethylene copolymer, and then the filler or pigment is added. The unstable end portion may be decomposed and removed at the time of blending.

  The unstable terminal portion can be decomposed and removed after the polymerization catalyst coexisting with the polyoxymethylene copolymer obtained by polymerization is deactivated, or can be performed without deactivating the polymerization catalyst. Is possible. Examples of the deactivation treatment of the polymerization catalyst include a method of neutralizing and deactivating the polymerization catalyst in a basic aqueous solution such as amines. When the polymerization catalyst is not deactivated, the copolymer is heated under an inert gas atmosphere at a temperature below the melting point of the polyoxymethylene copolymer, and the polymerization catalyst is reduced by volatilization, and then the unstable terminal. It is also an effective method to perform the disassembly and removal operation of the part.

  By the decomposition and removal treatment of the unstable terminal portion as described above, it is possible to obtain a polyoxymethylene copolymer having very little unstable terminal portion and excellent in thermal stability.

  Among these, more preferred polyoxymethylene resins include (A-1) a polyoxymethylene block copolymer having a number average molecular weight of 10,000 to 500,000 represented by the following general formula (1); or (A-2) It has an oxymethylene unit and an oxyalkylene unit having 2 or more carbon atoms, and the oxyalkylene unit is 0.1 to 10 mol%, preferably 0.1 to 5%, based on the total amount of the oxymethylene unit and the oxyalkylene unit. The polyoxymethylene copolymer which contains mol%, More preferably, 0.2-3 mol% is mentioned. Among these, a particularly preferable polyoxymethylene resin is (A-1) a polyoxymethylene block copolymer having a number average molecular weight of 10,000 to 500,000 represented by the following general formula (1). This (A-1) polyoxymethylene block copolymer can be produced by the method shown in International Publication WO01 / 009213.

H—R ³ —O— (CR ¹ ₂ ) _k —R ⁴ — (CR ¹ ₂ ) _k —O—R ³ —H (1)
In the formula, R ¹ represents a chemical species selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group, and a substituted or unsubstituted aryl group, and may be the same or different from each other. , K represents an integer of 2-6. R ³ represents a block having a plurality of oxymethylene units represented by the following general formula (2a) and oxyhydrocarbon units represented by the following general formula (2b), and the oxymethylene units and oxyhydrocarbon units are Randomly present, and the total amount of oxymethylene units and oxyhydrocarbon units is 100 mol%, the content of oxymethylene units is 95-99.9 mol%, the content of oxyhydrocarbon units is 0.1 5 mol%, and the average number average molecular weight of the two R ³ is 5000 to 250,000. R ² represents a chemical species selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group, and a substituted or unsubstituted aryl group, and may be the same or different from each other. An integer of 6 is shown. R ⁴ represents a block having a plurality of ethylene units represented by the following general formula (3a) and n-butylene units represented by the following general formula (3b), and the ethylene units and n-butylene units are random or The ethylene unit content is 2 to 98 mol% and the n-butylene unit content is 2 to 98 mol% with respect to 100 mol% of the total amount of ethylene units and n-butylene units. R ⁴ has a number average molecular weight thereof is 500 to 10,000, may have the following unsaturated bond iodine value 20g-I ₂ / 100g. )
_{- (CH 2 O) - (} 2a)
-((CR ² ₂ ) _j -O)-(2b)
_{- (CH 2 CH 2) -} (3a)
_{- (CH 2 CH 2 CH 2} CH 2) - (3b)

  Examples of the substituent in the substituted alkyl group and the substituted aryl group include a halogen atom, a hydroxyl group, an aldehyde group, a carboxyl group, an amino group, and an amide group.

  The component (A-1) is effective for improving compatibility with a polymer containing an olefin component, and in this respect, the component (A-1) is particularly preferably used alone. Moreover, when using (A-1) component together with (A-2) component, those mass ratios (A-1) / (A-2) are preferable in the range of 99/1 to 10/90. The range of 95/5 to 20/80 is more preferable, and the range of 95/5 to 70/30 is particularly preferable.

  The melt flow rate of the polyoxymethylene resin used in the present embodiment (measured under the conditions of ASTM-D1238-57T) is preferably 0.5 g / 10 min or more from the surface of molding, and 100 g from the viewpoint of durability. / 10 minutes or less, more preferably 1.0 to 80 g / 10 minutes, still more preferably 5 to 60 g / 10 minutes, and particularly preferably 7 to 50 g / 10 minutes.

  In the polyoxymethylene resin used in the present embodiment, a stabilizer used in the conventional polyoxymethylene resin, for example, one kind of heat stabilizer is used alone or in combination of two or more kinds. As the heat stabilizer, antioxidants, formaldehyde and formic acid scavengers, and combinations thereof are suitable. As the antioxidant, a hindered phenol antioxidant is preferable.

  Examples of the hindered phenol antioxidant include n-octadecyl-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) -propionate, n-octadecyl-3- (3′- Methyl-5′-t-butyl-4′-hydroxyphenyl) -propionate, n-tetradecyl-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) -propionate, 1,6- Hexanediol-bis- (3- (3,5-di-t-butyl-4-hydroxyphenyl) -propionate), 1,4-butanediol-bis- (3- (3,5-di-t-butyl) -4-hydroxyphenyl) -propionate), triethylene glycol-bis- (3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) -propionate) It is below.

  Examples of hindered phenol antioxidants include tetrakis- (methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate methane, 3,9-bis ( 2- (3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionyloxy) -1,1-dimethylethyl) -2,4,8,10-tetraoxaspiro (5,5) undecane N, N′-bis-3- (3 ′, 5′-di-t-butyl-4-hydroxyphenol) prepionylhexamethylenediamine, N, N′-tetramethylenebis-3- (3′- Methyl-5′-t-butyl-4-hydroxyphenol) propionyldiamine, N, N′-bis- (3- (3,5-di-t-butyl-4-hydroxyphenol) propionyl) hydra N-salicyloyl-N′-salicylidenehydrazine, 3- (N-salicyloyl) amino-1,2,4-triazole, N, N′-bis (2- (3- (3,5-di- Mention may also be made of butyl-4-hydroxyphenyl) propionyloxy) ethyl) oxyamide.

  Among these hindered phenolic antioxidants, triethylene glycol-bis- (3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) -propionate), tetrakis- (methylene-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate) methane is preferred.

  Formaldehyde and formic acid scavengers include compounds and polymers containing formaldehyde-reactive nitrogen, alkali metal or alkaline earth metal hydroxides, inorganic acid salts, and carboxylate salts. Examples of compounds and polymers containing formaldehyde-reactive nitrogen include dicyandiamide, melamine, co-condensates of melamine and formaldehyde, nylon 4-6, nylon 6, nylon 6-6, nylon 6-10, nylon 6-12. , Nylon 12, nylon 6 / 6-6, nylon 6 / 6-6 / 6-10, nylon 6 / 6-12 and other polyamide resins, poly-β-alanine, and polyacrylamide. Among these, a co-condensate of melamine and formaldehyde, polyamide resin, poly-β-alanine and polyacrylamide are preferable, and polyamide resin and poly-β-alanine are more preferable.

  Examples of alkali metal or alkaline earth metal hydroxides, inorganic acid salts, and carboxylate salts include hydroxides such as sodium, potassium, magnesium, calcium or barium, carbonates and phosphates of the above metals, Silicates, borates and carboxylates are mentioned. Specifically, calcium salts are most preferable, and are calcium hydroxide, calcium carbonate, calcium phosphate, calcium silicate, calcium borate, and fatty acid calcium salts (calcium stearate, calcium myristate, etc.), and these fatty acids are substituted with hydroxyl groups. It may be. Among these, fatty acid calcium salts (calcium stearate, calcium myristate, etc.) are preferable.

  Preferred combinations of stabilizers are in particular triethylene glycol-bis- (3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) -propionate) or tetrakis- (methylene-3- (3 ′, 5 ′ -Di-t-butyl-4'-hydroxyphenyl) propionate) a polymer comprising a hindered phenolic antioxidant represented by methane and in particular a polyamide resin and formaldehyde reactive nitrogen represented by poly-β-alanine And a fatty acid salt of an alkaline earth metal represented by a fatty acid calcium salt. The amount of each stabilizer added is 0.1 to 2 parts by mass of a hindered phenolic antioxidant and 0.1 to 3 parts of a polymer containing formaldehyde-reactive nitrogen with respect to 100 parts by mass of the polyoxymethylene resin. It is preferable that the mass part and the fatty acid salt of alkaline earth metal are in the range of 0.1 to 1% by mass.

  The resin composition of this embodiment contains (B) a polymer having at least one vinyl aromatic compound-conjugated diene compound copolymer block. The component (B) may be any polymer as long as it is a polymer having one or more blocks obtained by copolymerizing a vinyl aromatic compound and the above conjugated diene compound, or a hydrogenated product thereof.

  Component (B) is effective in improving impact resistance and vibration damping performance by adding it to the resin composition. As the component (B), specifically, a block comprising at least one polymer block X mainly composed of a vinyl aromatic compound and at least one vinyl aromatic compound-conjugated diene compound copolymer block Y. Copolymer, block copolymer comprising at least one polymer block Z mainly comprising a conjugated diene compound and at least one vinyl aromatic compound-conjugated diene compound copolymer block Y, vinyl aromatic compound And at least one polymer block X mainly composed of a conjugated diene compound and at least one vinyl aromatic compound-conjugated diene compound copolymer block Y. Block copolymer, vinyl aromatic compound-conjugated diene compound random copolymer, or hydrogenated products thereof . Here, the content of the vinyl aromatic compound in the polymer block X mainly composed of the vinyl aromatic compound is preferably 90% by mass or more, and the vinyl aromatic in the vinyl aromatic compound-conjugated diene compound copolymer block Y. The content of the compound is preferably 3% by weight or more and less than 90% by weight, and the content of the conjugated diene compound in the polymer block Z mainly composed of the conjugated diene compound is preferably 97% by weight or more.

  Among these, a block copolymer comprising at least one polymer block X mainly composed of a vinyl aromatic compound and at least one vinyl aromatic compound-conjugated diene compound copolymer block Y, a conjugated diene compound, A block copolymer comprising at least one polymer block Z mainly composed of at least one vinyl aromatic compound-conjugated diene compound copolymer block Y, at least one polymer composed mainly of a vinyl aromatic compound; A block copolymer comprising a polymer block X and at least one vinyl aromatic compound-conjugated diene compound copolymer block Y and at least one polymer block Z mainly composed of a conjugated diene compound, or these Hydrogenated products are preferred. The copolymer block in the block copolymer may be a random copolymer block, and the vinyl aromatic compound in the copolymer block may be uniformly distributed or tapered, that is, a copolymer. You may distribute so that the content may increase as it goes to the other from one side of a polymer block chain. Further, in the copolymer block, a plurality of blocks in which vinyl aromatic compounds are uniformly distributed and / or a plurality of blocks distributed in a tapered shape may coexist. Moreover, about this copolymer block, the block from which content of a vinyl aromatic compound differs may coexist.

As a block copolymer comprising at least one polymer block X mainly composed of a vinyl aromatic compound and at least one vinyl aromatic compound-conjugated diene compound copolymer block Y, for example, the following structure is used. Block copolymer having: (XY) _n , X- (YX) _n- Y, Y- (XY) _{n + 1} , [(XY) _k ] _{m + 1-} W , [(X−Y) _k −X] _{m + 1} −W, [(Y−X) _k ] _{m + 1} −W, and [(Y−X) _k −Y] _{m + 1} −W. . Here, W represents the residue of the coupling agent or the residue of the initiator of the polyfunctional organolithium compound. n, k, and m are each independently an integer of 1 or more, and are generally 1-5.

Examples of the block copolymer comprising at least one polymer block Z mainly composed of a conjugated diene compound and at least one vinyl aromatic compound-conjugated diene compound copolymer block Y include, for example, the following structures: That is, (ZY) _n , Z- (YZ) _n- Y, Y- (ZY) _{n + 1} , [(ZY) _k ] _{m + 1-} W, [(Z−Y) _k −Z] _{m + 1} −W, [(Y−Z) _k ] _{m + 1} −W, and [(Y−Z) _k −Y] _{m + 1} −W are exemplified. The Here, W represents the residue of the coupling agent or the residue of the initiator of the polyfunctional organolithium compound. n, k, and m are each independently an integer of 1 or more, and are generally 1-5.

Further, at least one polymer block X mainly composed of a vinyl aromatic compound, at least one vinyl aromatic compound-conjugated diene compound copolymer block Y, and at least one polymer mainly composed of a conjugated diene compound. Examples of the block copolymer composed of the block Z include, for example, block copolymers having the following structures, that is, (XYZ) _n , X- (YX) _n- Z, Z- (X- Y) _{n + 1} , [(X−Y−Z) _k ] _{m + 1} −W, [(X−Y−Z) _k −X] _{m + 1} −W, [(Y−X−Z) _k ] _{m + 1−} W, [(Y−X) _k −Z] _{m + 1} −W are exemplified. Here, W represents the residue of the coupling agent or the residue of the initiator of the polyfunctional organolithium compound. n, k, and m are each independently an integer of 1 or more, and are generally 1-5.

  Examples of the vinyl aromatic compound used in the polymer having at least one vinyl aromatic compound-conjugated diene compound copolymer block include styrene, α-methylstyrene, vinyltoluene, p-tert-butylstyrene, and diphenyl. One or more selected from the group consisting of ethylene are preferred, and styrene is particularly preferred. The content of the vinyl aromatic compound in the polymer having at least one vinyl aromatic compound-conjugated diene compound copolymer block is preferably from 3 to 90% by mass, more preferably from the total amount of the polymer. It is 5-88 mass%, More preferably, it is 10-86 mass%. When the content of the vinyl aromatic compound in the polymer having at least one vinyl aromatic compound-conjugated diene compound copolymer block is 50% by mass or less, preferably 40% by mass or less, the polymer is rubbery. When it exceeds 50 mass%, preferably exceeds 60 mass%, it exhibits high vibration damping performance. From the viewpoint of more effectively and reliably achieving the object of the present invention, the content of the vinyl aromatic compound is preferably 50 to 80% by mass, more preferably 55 to 75% by mass, and still more preferably 60 to 60%. It is in the range of 75% by mass.

  The content (mixing ratio) of the component (A) in the resin composition of the present embodiment is 20 to 99.5 with respect to 100 parts by mass of the total amount of the component (A), the component (B), and the component (C). It is a mass part, Preferably it is 20-95 mass parts, More preferably, it is 25-90 mass parts, Most preferably, it is 30-80 mass parts. When the component (A) is 20 parts by mass or more, the fluidity at the time of molding and the appearance of the molded product are good, and when it is 99.5 parts by mass or less, excellent vibration damping performance is imparted.

  Examples of the conjugated diene compound in the polymer having at least one vinyl aromatic compound-conjugated diene compound copolymer block include butadiene, isoprene, piperylene, and 1,3-pentadiene. The microstructure which is a polymerization form of the conjugated diene compound in the polymer having at least one vinyl aromatic compound-conjugated diene compound copolymer block is not particularly limited. For example, when the conjugated diene compound is butadiene, the amount of 1,2-vinyl bonds is preferably 2 to 2 with respect to the total amount of 1,2-vinyl bonds, 3,4-vinyl bonds and 1,4-vinyl bonds. 85%, more preferably 8 to 85%, still more preferably 10 to 85%. In the case where the conjugated diene compound is isoprene, the 1,2-vinyl bond and the 3,4-vinyl bond with respect to the total amount of 1,2-vinyl bond, 3,4-vinyl bond and 1,4-vinyl bond. The total amount is preferably 2 to 85%, more preferably 3 to 75%, and still more preferably 3 to 60%. And the conjugated diene compound polymer which is a precursor (prepolymer) of (B) component, and the number average of the polymer which has at least one vinyl aromatic compound-conjugated diene compound copolymer block which is (B) component The molecular weight (molecular weight in terms of polystyrene by gel permeation chromatography) is preferably 1,000 to 1,000,000, more preferably 10,000 to 800,000, still more preferably 30,000 to 500,000.

  A polymer having at least one vinyl aromatic compound-conjugated diene compound copolymer block is obtained by polymerizing a conjugated diene compound and a vinyl aromatic compound by anionic polymerization in a hydrocarbon solvent using an organic lithium compound as a polymerization initiator. Obtained. As the hydrocarbon solvent, aliphatic, alicyclic and aromatic hydrocarbons can be used. Specific examples include propane, isobutane, n-hexane, isooctane, cyclopentane, cyclohexane, benzene and toluene. . Among these, preferred solvents are n-hexane, cyclohexane and benzene. The hydrocarbon solvent is used alone or as a mixed solvent of two or more. Moreover, as an organic lithium compound which is a polymerization initiator used for polymerization, for example, mono-organic lithium compounds such as n-propyl lithium, isopropyl lithium, n-butyl lithium, sec-butyl lithium and tert-butyl lithium, and And polyfunctional organolithium compounds such as dilithiomethane, 1,4-dilithiobutane, 1,4-dilithio-2-ethylcyclohexane, 1,2-dilithio-1,2-diphenylmethane and 1,3,5-trilithiobenzene. It is done. These can be used individually by 1 type or in mixture of 2 or more types.

  The amount of the organic lithium compound used depends on the number average molecular weight of the polymer having at least one vinyl aromatic compound-conjugated diene compound copolymer block and is a monodisperse polymer (weight average molecular weight / number average molecular weight = 1). ) Can be selected as appropriate.

  In order to suppress the increase in the amount of 1,2-vinyl bond and 3,4-vinyl bond in the microstructure, which is the polymerization mode of the above conjugated diene compound, or in the vinyl aromatic compound-conjugated diene compound copolymer chain In order to adjust the randomness, polar compounds such as ethers, tertiary amines and alkali metal alkoxides can be used in the polymerization. Examples of such polar compounds include diethyl ether, ethylene glycol dimethyl ether, ethylene glycol di-n-butyl ether, ethylene glycol n-butyl-tert-butyl ether, ethylene glycol di-tert-butyl ether, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether, Tetrahydrofuran, α-methoxymethyltetrahydrofuran, dioxane, 1,2-dimethoxybenzene, triethylamine, N, N, N ′, N′-tetramethylethylenediamine, potassium-tert-amyl oxide, potassium-tert-butyl oxide, These compounds can be used individually by 1 type or in mixture of 2 or more types. The amount used in the case of using such a polar compound may be more than 0 mol, preferably more than 0 mol and 300 mol or less with respect to 1 mol of the organic lithium compound.

  Further, the polymer having at least one vinyl aromatic compound-conjugated diene compound copolymer block obtained here is subjected to a hydrogenation reaction by adding a hydrogenation catalyst and hydrogen gas in a hydrocarbon solvent. This reduces the olefinic unsaturated bond derived from the conjugated diene compound present in the polymer to 90% or less, preferably 80% or less, more preferably 55% or less, and even more preferably 20% or less before hydrogenation. A polymer hydrogenated product having at least one vinyl aromatic compound-conjugated diene compound copolymer block can be obtained. This hydrogenated product can also be used as the component (B). The smaller the amount of olefinically unsaturated bonds derived from the conjugated diene compound, the higher the aging resistance and light resistance. If the hydrogenation reaction can reduce the olefinic unsaturated bond derived from the conjugated diene compound present in the polymer having at least one vinyl aromatic compound-conjugated diene compound copolymer block, the production method thereof There is no limitation to this, and any manufacturing method may be used. Examples of the hydrogenation reaction include, for example, JP-B-42-8704, JP-B-43-6636, JP-A-60-220147, JP-A-61-33132, JP-A-62-207303. Examples thereof include methods described in Japanese Patent Publication No. GB1020720, U.S. Pat. Nos. 3,330,024 and 4,501,857. The hydrogenation rate of the hydrogenated product obtained by these methods can be easily known by infrared spectroscopic analysis, nuclear magnetic resonance analysis or the like.

  These (B) polymers having at least one vinyl aromatic compound-conjugated diene compound copolymer block or a hydrogenated product thereof have a tan δ main dispersion peak in the viscoelastic spectrum of 60 ° C. or less at room temperature (23 ° C. ) Excellent vibration control and noise reduction performance. Furthermore, from the viewpoint of vibration suppression / noise reduction, the main dispersion peak is preferably in the range of 60 to -30 ° C, more preferably in the range of 60 ° C to -20 ° C, and in the range of 50 to 0 ° C. Further preferred.

  The main dispersion peak of tan δ in the viscoelastic spectrum is measured as follows. First, a sheet-like sample is cut into a size of 10 mm in width and 35 mm in length, and the sample is set in a twist type geometry of a rheometer device (trade name “ARES”, manufactured by TI Instruments Inc.). . Next, the effective measurement length is set to 25 mm, the strain is set to 0.5%, the frequency is set to 1 Hz, and the temperature is increased from −80 ° C. to 80 ° C. at a temperature increase rate of 3 ° C./min to obtain a viscoelastic spectrum. The main dispersion peak temperature of tan δ in the obtained viscoelastic spectrum is a value obtained from a peak detected by automatic measurement of predetermined software (trade name “RSI Orchestrator”, manufactured by TI Instruments Inc.). .

  This (B) polymer having at least one vinyl aromatic compound-conjugated diene compound copolymer block or a hydrogenated product thereof can also be used as a dynamic crosslinking polymer.

  The content (mixing ratio) of the component (B) in the resin composition of the present embodiment is 0.25 to 79.79 with respect to 100 parts by mass of the total amount of the component (A), the component (B), and the component (C). The range is 2 parts by mass. When the component (B) is 79.2 parts by mass or less, the fluidity at the time of molding and the appearance of the molded product are good, and when it is 0.25 parts by mass or more, excellent vibration damping performance is imparted. The blending ratio of the component (B) is preferably in the range of 5 to 75 parts by mass, more preferably 10 to 70 parts per 100 parts by mass of the total amount of the components (A), (B) and (C). It is the range of a mass part, More preferably, it is the range of 20-70 mass parts.

  The oil resistance of the resin composition is improved by adding oil as component (C) to the resin composition of the present embodiment. Here, the oil may be either a mineral oil softener or a synthetic resin softener. The mineral oil softener is generally one or more softeners selected from the group consisting of aromatic hydrocarbons, naphthene hydrocarbons, and paraffin hydrocarbons, and is usually a mixture of these three softeners. is there. Paraffinic hydrocarbons with 50% or more carbon atoms in all carbon atoms are called paraffinic oils, and naphthenic hydrocarbons with 30 to 45% carbon atoms in all carbon atoms are naphthene. It is called a base oil, and an aromatic hydrocarbon having 35% or more carbon atoms is called an aromatic oil. Of these, the most preferred oil is paraffinic oil.

  As a paraffinic oil, the kinematic viscosity at 40 ° C. is preferably 20 to 800 cst (centistokes), more preferably 50 to 600 cst, and the fluidity is preferably 0 to −40 ° C., more preferably 0 to −30 ° C. Yes, those having a flash point (COC method) of preferably 200 to 400 ° C., more preferably 250 to 300 ° C. are used.

  Examples of synthetic resin softeners include polyalphaolefin softeners such as polybutene and low molecular weight polybutadiene, ester softeners such as polyol esters, diesters, and complex esters, dimethyl silicone, methylphenyl silicone, and methyl hydrogen. Examples include, but are not limited to, silicone softeners such as silicone and organically modified silicone.

  Content of (C) component in the resin composition of this embodiment is the range of 1-50 mass parts with respect to 100 mass parts of total amounts of (B) component and (C) component. The content thereof is preferably in the range of 3 to 40 parts by mass, and more preferably in the range of 5 to 35 parts by mass. When the content is 1 part by mass or more, the effect of oil resistance is enhanced, and when the content is 50% by mass or less, the impact resistance is extremely improved.

  A generally used melt-kneader can be used in the method for producing the resin composition of the present embodiment. Examples of the melt kneader include a kneader, a roll mill, a single screw extruder, a twin screw extruder, and a multi screw extruder. The processing temperature at the time of melt kneading is preferably 180 to 240 ° C., and in order to maintain the quality and working environment, the inside of the system is replaced with an inert gas, or deaeration is performed with single-stage and multistage vents. Is preferred.

  Moreover, after blending (A) component, (B) component, and (C) component uniformly with a blender, the method of kneading | mixing with an extruder may be sufficient, (C) component and (B) component are previously carried out. After mixing, the mixture may be mixed with the component (A) and melt-kneaded. Moreover, after knead | mixing (B) component and (C) component in the front | former stage of an extruder, the method of supplying (A) component to an extruder by side feed and kneading them may be sufficient. Alternatively, the component (B) and the component (C) may be kneaded in the preceding stage, and then the component (C) may be supplied to the extruder by side feed and then kneaded.

  The molded body of the present embodiment is obtained by molding the resin composition, and includes the resin composition. This molded body is injection molding method, hot runner injection molding method, outsert molding method, insert molding method, gas assist hollow injection molding method, high frequency heating injection molding method of mold, compression molding method, inflation molding, blow molding, It is formed by a forming method such as extrusion or cutting of an extruded product.

  Examples of such molded products include gears, cams, sliders, levers, arms, clutches, felt clutches, idler gears, pulleys, rollers, rollers, key stems, key tops, shutters, reels, shafts, joints, shafts, bearings, and guides. And mechanical parts represented by the above, outsert molded resin parts, and insert molded resin parts. Examples of the molded body include parts for office automation equipment such as chassis, tray, side plate, printer and copying machine, VTR (Video Tape Recorder), video movie, digital video camera, camera and digital camera. Camera or video equipment parts, cassette player, DAT, LD (Laser Disk), MD (Mini Disk), CD (CompactDisk) (CD-ROM (Read Only Memory), CD-R (Recordable), CD-RW (Including Rewritable)), DVD (Digital Versatile Disk) (including DVD-ROM, DVD-R, DVD-RW, DVD-RAM (Random Access Memory), DVD-Audio), other optical disk drives, MFD, Music, video or information represented by MO, navigation system and mobile personal computer Vessels, cellular phone and facsimile parts for communication equipment represented, parts for electrical equipment, and a component for electronic devices.

  In addition, the molded body is represented by automobile parts such as gasoline tanks, fuel pump modules, valves, fuel-related parts represented by gasoline tank flanges, door locks, door handles, window regulators, and speaker grills. Examples include parts around doors, slip rings for seat belts, press buttons, through anchors, seat belt peripheral parts represented by tongues, combination switch parts, switches and clips. Further, as the molded body, mechanical pencil parts for mechanical pencils and mechanical pencil cores, wash basins and drain outlets, drain plug opening / closing mechanism parts, vending machine opening / closing mechanism locking mechanism and product discharge mechanism parts, clothing Cord stoppers, adjusters and buttons, sprinkling nozzles and sprinkling hose connection joints, building supplies that support stair railings and flooring, disposable cameras, toys, fasteners, chains, conveyors, buckles, sports equipment, automatic Preferable examples include industrial parts such as vending machines, furniture, musical instruments, and housing equipment.

  The polyoxymethylene resin composition of the present embodiment is a material that imparts excellent impact resistance, vibration damping and noise reduction performance to the polyoxymethylene resin, and further improves oil resistance (grease resistance). The resin composition of the present embodiment is suitable as a material for parts in precision equipment, home appliances / OA equipment, automobiles, industrial materials, miscellaneous goods, and the like. The resin composition of the present embodiment is suitable for materials for office automation equipment, VTR equipment, music / video / information equipment, communication equipment, automobile interior / exterior parts, and industrial goods.

  Hereinafter, the present invention will be described specifically by way of examples. First, components and evaluation methods used in Examples and Comparative Examples are shown below.

(Each component)
(A) Polyoxymethylene resin (A-1) component A jacketed biaxial paddle type continuous polymerization machine capable of passing a heating medium is adjusted to 80 ° C., and 40 mol / kg of trioxane containing 4 ppm of water and formic acid is combined. At the same time, 1,3-dioxolane as a cyclic formal is 2 mol / hour, and boron trifluoride di-n-butyl etherate dissolved in cyclohexane as a polymerization catalyst is 5 × 10 ⁻⁵ mol per 1 mol of trioxane. As a chain transfer agent, the hydroxyl group-hydrogenated polybutadiene (Mn = 2330) represented by the following formula (7) is continuously added to the above polymerizer in an amount of 1 × 10 ⁻³ mol with respect to 1 mol of trioxane. To be polymerized. The polymer discharged from the polymerization machine was put into a 1% aqueous solution of triethylamine to completely deactivate the polymerization catalyst, and then the polymer was filtered and washed. As a quaternary ammonium compound, triethyl (2-hydroxyethyl) ammonium formate is added to 1 part by mass of the crude polyoxymethylene copolymer after filtration and washing so that the amount of nitrogen is 20 ppm by mass. They were mixed uniformly and then dried at 120 ° C.

  Next, triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] is used as an antioxidant with respect to 100 parts by mass of the crude polyoxymethylene copolymer after drying. 0.3 parts by mass and 0.02 parts by mass of calcium stearate were added and fed to a twin screw extruder with a vent. If necessary, water and / or triethylamine is added to the molten polyoxymethylene copolymer in the extruder under the conditions of a preset temperature of the extruder of 200 ° C. and a residence time of 5 minutes in the extruder. The stable end was decomposed. The polyoxymethylene copolymer in which the unstable terminal portion was decomposed was devolatilized under the condition of a vent vacuum of 20 Torr, extruded as a strand from the die portion of the extruder, and pelletized. The resulting block copolymer (A-1) polyoxymethylene resin has a flexural modulus of 2550 MPa, a melt flow rate of 9.3 g / 10 min (ASTM D-1238-57T), and a number average. The molecular weight was 52,000.

(A-2) Component A biaxial paddle type continuous polymerization machine with a jacket through which a heating medium can pass is adjusted to 80 ° C., and 40 mol / hour of trioxane containing 4 ppm of water and formic acid is simultaneously added as cyclic formal. Boron trifluoride di-n-butyl etherate dissolved in cyclohexane as a polymerization catalyst at a rate of 2 mol / hour, 5 × 10 ⁻⁵ mol per 1 mol of trioxane, methylal as a chain transfer agent Polymerization was carried out by continuously supplying [(CH ₃ O) ₂ CH ₂ ] to the polymerization machine in an amount of 2 × 10 ⁻³ mol per 1 mol of trioxane. The polymer discharged from the polymerization machine was put into a 1% aqueous solution of triethylamine to completely deactivate the polymerization catalyst, and then the polymer was filtered and washed. As a quaternary ammonium compound, triethyl (2-hydroxyethyl) ammonium formate is added to 1 part by mass of the crude polyoxymethylene copolymer after filtration and washing so that the amount of nitrogen is 20 ppm by mass. They were mixed uniformly and then dried at 120 ° C.

  Next, triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate] is used as an antioxidant with respect to 100 parts by mass of the crude polyoxymethylene copolymer after drying. 0.3 parts by mass and 0.02 parts by mass of calcium stearate were added and fed to a twin screw extruder with a vent. If necessary, water and / or triethylamine is added to the molten polyoxymethylene copolymer in the extruder under the conditions of a preset temperature of the extruder of 200 ° C. and a residence time of 5 minutes in the extruder. The stable end was decomposed. The polyoxymethylene copolymer in which the unstable terminal portion was decomposed was devolatilized under the condition of a vent vacuum of 20 Torr, and extruded as a strand from the extruder die to form pellets. The obtained (A-2) polyoxymethylene resin had a flexural modulus of 2600 MPa, a melt flow rate of 9.0 g / 10 minutes (ASTM D-1238-57T), and a number average molecular weight of 55,000.

(B) Polymer having at least one aromatic vinyl compound-conjugated diene compound copolymer block or hydrogenated product thereof In a cyclohexane solvent in a reactor equipped with a stirrer substituted with nitrogen gas, n-butyllithium is a polymerization initiator. A styrene-butadiene copolymer having an XYX structure and having a number average molecular weight of 100,000 and a molecular weight distribution of 1.1 was obtained by polymerization. The content of all blocks X in the copolymer was 15% by mass, the total amount of styrene bonded was 62% by mass, and the amount of 1,2-vinyl bonds in the butadiene portion was 30%. Thereafter, the polymerization liquid is transferred to another reactor substituted with nitrogen gas, and a hydrogenation reaction is performed on the ethylenically unsaturated bond of the polybutadiene portion by the method described in US Pat. No. 4,501,857, A polymer with an addition rate of 50% was obtained. 0.3 parts by mass of octadecyl-3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate as a heat degradation stabilizer is added to 100 parts by mass of the polymer after the hydrogenation reaction. The solvent, cyclohexane, was removed by heating. In this way, a hydrogenated polymer having at least one aromatic vinyl compound-conjugated diene compound copolymer block having a hydrogenated XYX structure was obtained. The main dispersion peak temperature of tan δ in the viscoelastic spectrum of this polymer was 10 ° C.

(C) Diana process oil PW380 (made by Idemitsu Kosan Co., Ltd., trade name) was used as the oil.

[Evaluation method]
(1) Evaluation of mechanical properties After pellets obtained in Examples and Comparative Examples were dried at 80 ° C. for 3 hours, a 5-ounce molding machine (manufactured by Toshiba Machine Co., Ltd., trade name “ IS-100GN "), an ISO dumbbell test piece for evaluating physical properties was molded under conditions of a mold temperature of 90 ° C, an injection time of 35 seconds, and a cooling time of 15 seconds. The following tests were performed on this test piece.
(I) Tensile elongation: measured based on ISO 527-1 & -2.
(Ii) Charpy impact strength; measured based on ISO 179 / 1eA.

(2) Oil resistance After the pellets obtained in Examples and Comparative Examples were dried at 80 ° C. for 3 hours, a 5-ounce molding machine set to a cylinder temperature of 200 ° C. (trade name “IS-” manufactured by Toshiba Machine Co., Ltd.) 100 GN "), 30φ gear specimens were molded under conditions of a mold temperature of 70 ° C, an injection time of 20 seconds, and a cooling time of 15 seconds. The test piece was tested for oil resistance as follows.

  First, the gear inner diameter (D1) of the test piece was measured using a micro gauge. Thereafter, grease (trade name “PG641”, olefin grease, manufactured by Dow Corning) was applied to the opening of the test piece, and heat treatment was performed in a gear oven heated to 70 ° C. for 9 hours. After removing the test piece from the oven, the grease was wiped off, the gear inner diameter (D2) of the test piece was measured, and ((D1)-(D2)) was evaluated as oil resistance (μm).

(3) Loss coefficient In the anechoic chamber, one end of a test piece similar to that used for mechanical property evaluation was fixed, and the sound emitted when the root of the fixed end was struck with an impulse hammer. The loss coefficient was obtained from the frequency response function of the hammer excitation force signal and the microphone sound pressure signal using an acoustic analysis system manufactured by Ono Sokki Co., Ltd. A large loss factor (%) means excellent vibration control and noise reduction performance.

[Example 1]
(A-1) 20 parts by mass of component and 62 parts by mass of component (B) were mixed uniformly with a blender, and then the mixture was L / D = 48 26 mmφ twin-screw extruder set at 200 ° C. (Toshiba Machine) The product was supplied to the top of a product name “TEM-26SS” using a weight type feeder. Furthermore, 18 parts by mass of component (C) was supplied to the extruder using a liquid addition apparatus, and melt kneading was performed under the conditions of a screw rotation speed of 120 rpm and an extrusion speed of 11 kg / hour. The extruded resin composition was pelletized with a strand cutter. The above various measurements were performed on the obtained pellets. The results are shown in Table 1.

[Example 2]
Component (A-1) 20 parts by mass, component (B) 62 parts by mass, and triethylene glycol-bis- [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate] as a stabilizer 0.3 parts by mass, 0.05 part by mass of polyamide 66, and 0.13 parts by mass of calcium stearate were uniformly mixed with a blender, and then L / D = 48 26 mmφ biaxial extrusion set at 200 ° C. The top of the machine (trade name “TEM-26SS” manufactured by Toshiba Machine Co., Ltd.) was supplied using a weight type feeder. Furthermore, 18 parts by mass of component (C) was supplied to the extruder using a liquid addition apparatus, and melt kneading was performed under the conditions of a screw rotation speed of 120 rpm and an extrusion speed of 11 kg / hour. The extruded resin composition was pelletized with a strand cutter. The above various measurements were performed on the obtained pellets. The results are shown in Table 1.

[Example 3]
(B) Using a weight type feeder at the top of a 26 mmφ twin screw extruder (manufactured by Toshiba Machine Co., Ltd., trade name “TEM-26SS”) with 77 parts by mass of component set to 200 ° C., L / D = 48 Then, 23 parts by mass of component (C) were supplied to the extruder using a liquid addition apparatus, and melt kneading was performed under the conditions of a screw rotational speed of 150 rpm and an extrusion speed of 15 kg / hour. The extruded resin composition was pelletized with a strand cutter. 80 parts by mass of the obtained resin composition of component (B) and component (C), 20 parts by mass of component (A-1), and triethylene glycol-bis- [3- (3-t-butyl as a stabilizer) -5-methyl-4-hydroxyphenyl) propionate] 0.3 parts by weight, polyamide 66 0.05 parts by weight, calcium stearate 0.13 parts by weight, and after mixing uniformly with a blender, Supply to the top of the set 26mmφ twin screw extruder (trade name “TEM-26SS” manufactured by Toshiba Machine Co., Ltd.) with L / D = 48 using a weight type feeder, screw rotation speed 120rpm, extrusion speed Melt kneading was performed under conditions of 11 kg / hour. The extruded resin composition was pelletized with a strand cutter. The above various measurements were performed on the obtained pellets. The results are shown in Table 1.

[Examples 4 to 8]
A pellet was obtained in the same manner as in Example 3 except that the composition (unit: part by mass, the same applies hereinafter) of the component (A-1), the component (B), and the component (C) was changed as shown in Table 1. It was. The above various measurements were performed on the obtained pellets. The results are shown in Table 1.

[Examples 9 to 11]
A pellet was obtained in the same manner as in Example 5 except that the component (A-1) and the component (A-2) were used as the component (A) in the composition shown in Table 1. The above various measurements were performed on the obtained pellets. The results are shown in Table 1.

[Comparative Examples 1-5]
A pellet was obtained in the same manner as in Example 3 except that the component (A-1) and / or the component (A-2), the component (B), and the component (C) were used in the composition shown in Table 1. The above various measurements were performed on the obtained pellets. The results are shown in Table 2.

  The polyoxymethylene resin composition of the present invention is a mechanical component (for example, gear, cam, slider, lever, arm, clutch, joint, shaft, bearing, key stem and key) obtained by molding, cutting, or molding / cutting. At least one member selected from the group consisting of the top), at least one member selected from the group consisting of the resin component of the outsert chassis, the chassis, the tray and the side plate, and can be used for the following applications. (1) Parts used for OA equipment represented by printers and copiers, (2) Parts used for video equipment represented by VTRs and video movies, (3) Cassette players, LD, MD, CD (including CD-ROM, CD-R, CD-RW), DVD (including DVD-ROM, DVD-R, DVD-RAM, DVD-Audio), music, video represented by navigation systems and mobile computers, or Parts used for information equipment, (4) Parts used for communication equipment represented by mobile phones and facsimiles, (5) Clips, through anchors, tongues, fuel tanks, fuel used for automobile interior and exterior parts Parts used for the tank and its peripheral parts, and (6) disposable cameras, toys, fasteners, conveyors, buckles And there is a APPLICABILITY industry parts used in industrial goods represented by housing equipment.

Claims (5)

(A) a polymer having at least one polyoxymethylene resin and (B) a vinyl aromatic compound-conjugated diene compound copolymer block, wherein the main dispersion peak of tan δ in the viscoelastic spectrum is 60 ° C. or less, or a polymer thereof Containing hydrogenated product and (C) oil,
The content of the component (A) is 20 to 99.5 parts by mass with respect to 100 parts by mass of the total of the component (A), the component (B), and the component (C), and the component (B) ) Component content is 0.25-79.2 parts by mass,
The content of the component (C) is 1 to 50 parts by mass with respect to a total amount of 100 parts by mass of the component (B) and the component (C),
The component (A) includes (A-1) a polyoxymethylene block copolymer having a number average molecular weight of 10,000 to 500,000 represented by the following general formula (1):
The component (C) is a polyoxymethylene resin composition comprising a mineral oil softener or a synthetic resin softener selected from the group consisting of dimethylsilicone, methylphenylsilicone and methylhydrogensilicone .
^{H-R 3 -O- (CR 1} 2) k-R 4 - (CR 1 2) k-O-R 3 -H (1)
(Wherein R ¹ represents a chemical species selected from the group consisting of a hydrogen atom, a substituted or unsubstituted alkyl group, and a substituted or unsubstituted aryl group, and may be the same or different from each other; Represents an integer of 2 to 6. R ³ represents a block having a plurality of oxymethylene units represented by the following general formula (2a) and oxyhydrocarbon units represented by the following general formula (2b); The methylene unit and the oxyhydrocarbon unit are present randomly, and the content of the oxymethylene unit is 95 to 99.9 mol with respect to 100 mol% of the total amount of the oxymethylene unit and the oxyhydrocarbon unit. %, and 0.1 to 5 mol% content of the oxyhydrocarbon units, number average molecular weight of the average of the two R ³ is 5000 to 250000 .R ² is a hydrogen atom, a substituted or unsubstituted Alkyl group, and shows the species selected from the group consisting of substituted or unsubstituted aryl group, which may be the being the same or different, j is an integer of 2 to 6 .R ⁴ represented by the following general formula 2 shows a block having a plurality of ethylene units represented by (3a) and n-butylene units represented by the following general formula (3b), wherein the ethylene units and the n-butylene units are present at random or in blocks. The ethylene unit content is 2 to 98 mol% and the n-butylene unit content is 2 to 98 mol% with respect to 100 mol% of the total amount of the ethylene unit and the n-butylene unit. R ⁴ has a number average molecular weight of 500 to 10,000 and may have an unsaturated bond having an iodine value of 20 g-I 2/100 g or less.)
_{- (CH 2 O) - (} 2a)
− ((CR ² ₂ ) j−O) − (2b)
_{- (CH 2 CH 2) -} (3a)
_{- (CH 2 CH 2 CH 2} CH 2) - (3b)   The component (A) has (A-2) an oxymethylene unit and an oxyalkylene unit having 2 or more carbon atoms, and the total amount of the oxymethylene unit and the oxyalkylene unit, It further contains a polyoxymethylene copolymer having a content of 0.1 to 10 mol%, and the mass ratio (A-1) / (A-2) of the component (A-1) to the component (A-2) The polyoxymethylene resin composition according to claim 1, wherein 99) is 99/1 to 10/90.   The polyoxymethylene resin composition according to claim 1, wherein the component (A) comprises the component (A-1).   The polyoxymethylene resin composition according to any one of claims 1 to 3, wherein a main dispersion peak of the tan δ in the viscoelastic spectrum of the component (B) is 60 ° C to -20 ° C.   The molded object containing the polyoxymethylene resin composition as described in any one of Claims 1-4.